M. Sakthivel

pH-sensitive Itaconic acid based polymeric hydrogels for dye removal applications

A series of Itaconic Acid (IA) based pH-sensitive polymeric hydrogels were synthesized by condensation polymerization of Itaconic Acid (IA) with Ethylene Glycol (EG) in the presence of an acid medium resulted into pre-polymer. Further, pre-polymer were co-polymerized with Acrylic Acid (AA) through free radical polymerization using Potassium persulphate (KPS). The structural and surface morphological characterizations of the synthesized hydrogels were studied using FT-IR spectroscopy and Scanning Electron Microscope (SEM) respectively. The swelling and swelling equilibrium were performed at varies pH (4.0-10.0). Further, the effects of IA, EG and AA on swelling properties have also been investigated. Thermal stability of synthesized hydrogels have been investigated by TGA, DTA and DSC. The synthesized hydrogels have shown good ability to uptake a Cationic dye. The Methylene blue has been chosen as a model cationic dye. The results of dye removal using IA hydrogels found to have excellent dye removal capacity. Such kind of IA based hydrogels may be recommended for eco-friendly environmental application. viz., removal of dyes and metal ions and sewage water treatment, purification of water etc.

Non toxic, antibacterial, biodegradable hydrogels with pH-stimuli sensitivity: Investigation of swelling parameters

In this work, a series of pH-sensitive hydrogels were synthesized from Sodium alginate (SA), Ethylene glycol (EG) and Acrylic acid (AA). Biodegradability of hydrogel was tested against soil burial test for 35days and in vitro phosphate buffer solution test for 10days respectively. Degradation of the sample might be due to the breakdown of ester linkage and hydrophilic pendant functionality present in hydrogel. The progression of biodegradation was examined by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Detailed swelling parameters such as swelling equilibrium Seq (%) at various pH, biological fluids (distilled water (DW), physiological saline 0.89% NaCl (PS), iso-osmotic phosphate buffer at pH 7.4 (PB)) and equilibrium water content (EWC) have also been investigated, which revealed that dynamic compassion of hydrogels. The hydrogel has shown strong antibacterial activity against Escherichia coli (gram negative) and Staphylococcus aureus (gram positive) bacterias. Cytotoxic assays, using MTT Assay in 3T3 fibroblast Cell line was performed. At 10μg/ml, cell viability was in the range of 92-94%. However, the cell viability (%) decreases with increasing concentration of sample. The synergistic effect of biodegradable hydrogels possessing excellent swelling properties, high water content, biocompatibility and wound healing tendency using in vivo test can be made as suitable candidate for biomedical applications. In vivo wound healing studies conducted on a Wister albino rat model of incision wound performed for 9days. The results revealed that more accelerated wound healing have been observed even in shorter duration. Thus, the synthesized hydrogel with great pH-responsiveness and excellent drug delivery may have a great opening for biomedical applications.

Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels

The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications.

Investigation on pH-switchable (itaconic acid/ethylene glycol/acrylic acid) based polymeric biocompatible hydrogel

In this paper, a new variety of pH-sensitive polymeric hydrogels (IAE) have been developed and evaluated as biocompatible hydrogels using synergetic combinations of itaconic acid (IA), acrylic acid (AA), and ethylene glycol (EG) in water medium by free radical polymerization. The prepared hydrogels were characterised by FT-IR and SEM, which revealed the presence of functional groups and the morphological aspects of the IAE based hydrogels. The detailed swelling behaviour of various stoichiometric amounts of IAE based hydrogels has been studied at varying pH (1.2, 6.0, 7.4 and 10.0) with respect to time from 0 to 360 minutes. The comparative swelling equilibrium, biodegradation and biocompatibility studies of hydrogels have also been investigated. The antibacterial activities of the IAE based hydrogels were examined using pathogenic microorganisms viz. E. coli, S. aureus and B. cereus. Furthermore, the IAE hydrogels were also subjected to antifungal activity against Aspergillus niger & Candida albicans using the agar well diffusion method at various concentrations. The improved biocompatible properties of these gels imply that the IAE hydrogels have good potential for future biomedical applications in controlled drug release.

Preparation, antimicrobial and antioxidant evaluation of indole-3-acetic acid-based pH-responsive bio-nanocomposites

Nanocomposites were synthesized among citric acid, ethylene glycol and indole-3-acetic acid by condensation followed by incorporating silver nanoparticles (AgNPs) in a hydrogel. The formation of parent hydrogel and their nanocomposites were identified by Fourier transform infrared spectroscopy. The incorporation of silver nanoparticles in the hydrogel network, surface morphology and size of nanoparticles were established by ultraviolet spectroscopy, scanning electron microscopy and transmission electron microscopy, respectively. The thermal properties of the hydrogels were studied by TGA–DTA analysis. The parent hydrogel (ICE) and nanocomposites revealed a good pH-sensitive swelling behavior at acidic media than in basic media. In vitro examination of fungal activity revealed all prepared hydrogels as effective against Aspergillus fumigatus, Rhizopus oryzae and Candida albicans. Further, the antibacterial properties of the optimum sample were successfully evaluated against Gram-positive (Bacillus aureus, Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The prepared nanocomposites showed a higher antimicrobial activity than that of the parent hydrogel. Further, the radical scavenging ability of the hydrogel and nanocomposites were estimated using DPPH (2,2-diphenyl-1-picryl-hydrazyl) and nitric oxide radicals. The prepared nanocomposites with tuned antibacterial, antifungal and antioxidant properties can be used for wound healing, burn dressing, treatment of topical fungal infections and for other biomedical applications.

Indole-3-acetic acid/diol based pH-sensitive biological macromolecule for antibacterial, antifungal and antioxidant applications

Indole-3-acetic acid (IAA)/diol based pH-sensitive biopolymeric hydrogels with tunable biological properties (cytotoxicity, anti-oxidant and anti-fungal) have been synthesized via condensation polymerization. The present study focused on the synthesis of heterocyclic hydrogel using citric acid (CA), indole-3-acetic acid (IAA) and diethylene glycol (DEG) by condensation polymerization. The hydrogels revealed a pH-sensitive swelling behaviour, with increased swelling in acidic media, then turns to decreased the swelling in the basic media. The hydrogel samples were tested for antifungal activity against Aspergillus fumigates, Rhizopusoryzae and Candida albicans at different concentrations using ketoconazole as positive control and DMSO as negative control for antifungal activity. Antioxidant activity increasing nature in DPPH than NO radical compared with rutin and confirmed non toxic property using cytotoxicity analysis. The biopolymeric hydrogels were characterized by Fourier transform infrared (FT-IR) spectroscopy, 1H NMR,13C NMR, TGA, DSC followed by scanning electron microscopy (SEM). Such hydrogels with antioxidant properties is recommended for medical applications such as bandages, catheters, drains and tubes to prevent infection.